Electrochemical immunoassay of hepatitis B surface antigen by the amplification of gold nanoparticles based on the nanoporous gold electrode

We describe herein the combination of electrochemical immunoassay using nanoporous gold (NPG) electrode with horseradish peroxidase (HRP) labeled secondary antibody-gold nanoparticles (AuNPs) bioconjugates for highly sensitive detection of protein in serum. The electroactive product of o-phenylenediamine (OPD) oxidized with H₂O₂ catalyzed by HRP was reduced in the Britton-Robinson (BR) buffer and the peak current of which was used to determine the concentration of antigen (Ag) in the analyte. The active surface area of NPG electrode was larger than that of a bare flat one. The presence of AuNPs enhanced the immobilized amount of HRP labeled antibody (Ab), which improved the sensitivity of the immunoassay when used as the secondary antibodies. As a result of these two combined effects, the sensitivity of the immunoassay for the determination of target protein was increased significantly. Using hepatitis B surface antigen (HBsAg) as a model, we demonstrate a dose response in the range of 0.01-1.0 ng/mL with a detection limit of 2.3 pg/mL. Analytical results of several human serum samples obtained using the developing technique are in satisfactory agreement with those given by enzyme-linked immune-absorbent assays (ELISA). In addition, the technique was about 100 times more sensitive in the detection of HBsAg than ELISA. All these demonstrated the feasibility of the present immunoassay method for clinical diagnosis.     

Differential Pulse Voltammetric Detection of Hepatitis C Virus 1a Oligonucleotide Chain by a Label‐Free Electrochemical DNA Hybridization Biosensor Using Consensus Sequence of Hepatitis C Virus 1a Probe on the Pencil Graphite Electrode

The short sequence related to hepatitis C virus (HCV1) is detected by a label‐free DNA hybridization biosensor. The sensor relies on the immobilization of a 20‐mer oligonucleotide containing 2 guanine and 11 cytosine bases denoted PHCV1 as probe on the pencil graphite electrode (PGE). The hybridization event was monitored by differential pulse voltammetry (DPV) using the guanine signal. The selectivity of the biosensor was studied using some noncomplementary oligonucleotides. Diagnostic performance of the biosensor is described and the detection limit was found to be 6.5 nM.     

由质谱分析数据建立乙肝病人与健康人的分类模型

建立运用表面加强激光解吸电离-飞行时间质谱获取乙肝病人和健康人血清蛋白指纹图谱数据,并用偏最小二乘(PLS)变量筛选法建立乙型肝炎(HBV)病人和健康人的分类模型,最终得到分类模型的交叉检验相关系数达0.97以上,判别准确率显著提高.对模型进行分析,找出对乙型肝炎病人和健康人的差异有重要影响的因素或变量.这些变量为某些质荷比区间内特定蛋白的峰强度值,反映这些质荷比区间内蛋白量的增加或减少,与乙肝病的形成有密切关系,可作为重要的生物标志物,进一步加以研究.本研究采用所得模型的拟合值等一些信息来做分类图,能较好地表达回归模型的分类效果.     

Biosensors in Wine Production Monitoring

ABSTRACT

An overview of probe-type and flow-through biosensors, together with biosensing systems, both batch and continuous biosensing systems, for monitoring typical species in wine processes is presented with the aim of showing the advantages and disadvantages involved in the use of each type of devices. Thus, biosensors and biosensing systems for the determination of ethanol (individual or together with that of other compounds), organic acids, glycerol, reducing sugars, acetaldehyde and sulfur dioxide/sulfite anions are reviewed and critically compared. The versatility and capability of continuous biosensing systems as compared with biosensors, particularly with probe-type biosensors working in a discontinuous, batch manner, is demonstrated.     

Polarographic Enzyme-Immunoassay for Trace Hepatitis B Surface Antigen

Abstract

A polarographic enzyme-immunoassay for Hepatitis B Surface Antigen(HBsAg) has been established, in which horseradish peroxidase(HRP) is used as the labeled enzyme, o-phenylenediamine(OPD) as the substrate, and the enzyme-generated product,2,2′-diaminoazobenzene (DAA). is detected by linear-potential scan polarography. Under optimal conditions, the second derivative current of DAA is linear with the concentration of HBsAg from 0.1 to 5 ng/mL. The correlation coefficient(r) is 0.9994. The detection limit is 0.05ng/mL and the relative standard deviation is 6.7%(8 replicates). The sensitivity of the assay is about 20-fold higher than that of ELISA. The assay has been successfully applied for minute determination of HBsAg in both human serum and the negative control serum from ELISA kits.     

Transmission dynamics and the control of hepatitis B in China: a population dynamics view

Though the prevalence of hepatitis B began to decline for the first time in 2010, it remains unclear whether this downward trend is permanent and the disease will be eradicated in mainland China under the current measures. Because a large number of hepatitis B virus (HBV) carriers and unknown HBV infections is characteristic of HBV infections in China, a mathematical model was designed and fitted to the reported hepatitis B data. The estimated basic reproduction number is 1.2861 (95\% confidence interval (CI) 1.2386-1.3302), which remains greater than one. Thus, the decline in 2010 may be part of the temporary benefits of public policy measures and should not be interpreted as indicative of successful intervention, although interventions do provide some benefits. To assess the effects of various interventions, the global uncertainty and sensitivity analyses revealed that the contribution of carriers is always greater than that of acute infections, and the prevalence of hepatitis B in China may be primarily a result of transmission by unknown patients. Therefore, strategies for controlling the HBV endemic, which target known patients, are unlikely to be highly effective. Additionally, three feasible strategies are proposed, although the benefits of these strategies may change radically over time.     

On Modeling Hepatitis B Transmission Using Cellular Automata

Hepatitis B transmission is shown to be dilficult to model using differential equations, but easily modeled using cellular automata.     

Evaluating the inhibitory effect of eight compounds from Daphne papyracea against the NS3/4A protease of hepatitis C virus

Abstract

Hepatitis C virus (HCV) infection is a global threat to human health with an estimated 1.75 million new cases in 2015. Our previous studies showed that the ethyl acetate extraction of Daphne papyracea exhibited an inhibitory effect towards the HCV NS3/4A protease and eight compounds were identified from the extract. In this study, we investigated which of the eight compounds was responsible for the inhibitory effect of the extract against the HCV NS3/4A protease. From both molecular docking and enzyme inhibition studies, (+)-usnic acid was shown to be the most active compound and could be used as a lead compound in developing novel anti-HCV agents.     

小儿甲型肝炎早期血清锌、铜、铁、镁含量变化的探讨

通过对９８例甲型肝炎早期住院患儿血清锌、铜、铁、镁含量的检测，显示在小儿甲型肝炎早期，血清锌、镁含量与对照组无显著差异（Ｐ＞０．０５），血清铜、铁含量明显增高，与对照组存在非常显著差异（Ｐ＜０．０１）．文章对甲型肝炎患儿血清锌、铜、铁含量的变化和临床意义进行了探讨．     

双缩水甘油醚活化法制备免疫吸附剂及其对乙型肝炎表面抗原的吸附

采用1,4－二羟基正丁烷双缩水甘油醚活化交联壳聚糖树脂,偶联抗－乙型肝炎表面抗原单克隆抗体,制备树脂／抗体免疫吸附剂,对含乙型肝炎表面抗原的患者阳性血清的吸附试验结果表明,吸附率可达44％,能使阳性血清转为阴性。